Helical wound flexible torque transmission cable

ABSTRACT

A cable adapted to transmit torque in rigging or furling a sail of a boat includes a core having at least one termination end and a bight, and at least one layer of fiber wound around the core, wherein a fiber in a portion of the fiber layer disposed over a center portion of the bight has a first pitch angle relative to a longitudinal axis of the core and wherein a fiber in a portion of the fiber layer disposed over the at least one termination end has a second pitch angle relative to the longitudinal axis of the core. The fiber layer includes a transition zone disposed between the at least one termination end and the center portion, wherein a fiber in the transition zone has an orientation that transitions from the first pitch angle to the second pitch angle.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a Divisional application of U.S. patentapplication Ser. No. 13/706,491, filed on Dec. 6, 2012.

FIELD OF THE INVENTION

The invention relates to a rigging and furling device for sailboats andmore specifically to a luff rope or cable that is capable of providingefficient torque transmission and withstanding high tension, and has afiber structure which resists breakdown as a result of repeated use.

BACKGROUND OF THE INVENTION

There are many rope and cable products in the market that are used inrigging and furling applications. These conventional rope products serveas inexpensive assemblies that work sufficiently in various sailingconditions. Nevertheless, as sail boats increase in size and/or theirsails become larger (e.g., larger luff length), the performance ofconventional ropes becomes increasingly worse. In particular, they lackrigging/furling efficiency and safety.

A luff rope, in particular, is adapted to transmit torque up from afurler to a top swivel. Some luff ropes are described in U.S. Pat. No.4,124,971 to Taylor et al. and U.S. Pat. No. 8,117,817 to Markham et al.For the luff rope to be effective in furling systems, numerous turnsmust be applied to the furler drum to “pre-twist” the luff rope and thusgenerate and transfer torque quickly up to the top swivel. Thepre-twisting may reduce the time needed to furl a sail but may alsocause an instantaneous furl at or near the top swivel. This negativeoutcome results in a very tight and often detrimental wrapping of thesail. In addition, the act of pre-twisting may cause the sail tooverwrap about the luff rope due to the instantaneous furl. Bypre-twisting the luff rope, an excess of energy is stored therein, whichcauses the rope to become uncontrollable when the process of furling isinitiated.

Conventional luff ropes often comprise a central core of high strengthmaterial (e.g., polybenzoxazole (PBO), Kevlar®, Technora®) and multiplelayers of fiber braided over the central core with adhesive disposedbetween the fiber layers and the core. The fiber layers may further beimpregnated with resin to improve the tensile strength of eachindividual fiber. However, conventional ropes are not able to transmittorque efficiently and safely in furling systems (e.g., top-downfurling). They have a tendency to break down with repeated use,especially when they are subjected to high tension and torque. The resinbinding the fibers can fail due to the overall flexibility of the luffrope as well as fiber movement caused by core compression and rope/cablecoiling. In addition, conventional ropes often form kinks when they aretightly coiled or flaked for stowage.

While conventional ropes and cables may work with furling systems, theystill suffer from several disadvantages. One disadvantage is thatconventional ropes fail to provide efficient torque transmissionproperties without relying on resin-impregnated fibers. Anotherdisadvantage is that conventional ropes often malfunction in furlingsystems, either wrapping the sail too tightly or overwrapping the sail.Moreover, the ropes, and specifically their resin-impregnated fibers,are prone to break down or experience damage after repeated furling andcoiling. It is therefore desired to overcome these disadvantages andprovide a cable that has improved torque transmission characteristics.It is also desired to provide a cable that is robust and avoids physicalbreakdown and deterioration of performance associated therewith. It isfurther desired to provide a cable that does not require the infusion ofresin into fibers in order to achieve high tensile strength andefficient torque transmission.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to remedy theproblems of conventional ropes which fail to provide quick and efficientfurling of a sail. The present invention provides a cable for efficienttorque transmission in rigging or furling sails of all sizes.

It is a further object to provide a torque transmission cable having aflexible structure that can withstand fiber breakage caused by corecompression, cable coiling, high tensile force applied to the cable,and/or high torque applied to the cable.

It is an additional object to provide a torque transmission cablewherein fibers of the cable become tensioned when the cable itself istensioned axially.

It is another object to provide a torque transmission cable that isadapted to provide a high rate of torque transfer without requiringpre-twisting, or at least substantial pre-twisting, of the cable withina furler drum of a furling system.

These and other objectives are achieved by providing a cable adapted totransmit torque in rigging or furling a sail of a boat including a corehaving a termination end and a bight, and one layer of fiber wrapped orwound around the core, wherein at least one fiber in a portion of thefiber layer disposed over a center portion of the bight has a firstpitch angle relative to a longitudinal axis of the core, wherein atleast one fiber in a portion of the fiber layer disposed over thetermination end has a second pitch angle relative to the longitudinalaxis, and wherein the fiber layer comprises a transition zone disposedbetween the at least one termination end and the center portion of thebight. At least one fiber in the transition zone has an orientation thatchanges from the first pitch angle to the second pitch angle. Thetransition zone defines the part of the cable where the fiber maintainsa pitch angle which gradually transitions from the first pitch angle tothe second pitch angle.

Noted herein, the term “bight” defines the middle part of a cable orrope, as distinguished from the ends.

In some embodiments, the first pitch angle is less than the second pitchangle. Accordingly, the angle of the fiber increases from the centerportion of the bight towards the termination end. In alternativeembodiments, the first pitch angle is greater than the second pitchangle, such that the pitch angle of the fiber decreases from the centerportion of the bight towards the termination end. The gradualtransitioning of pitch angle of the fiber layer is adapted to aid intransmitting torque load quickly and efficiently.

Further objectives are achieved by providing a torque transmission cablehaving at least one termination end and a bight, at least one layer offiber wound around the core, and a transmission zone where theorientation of at least one fiber in the fiber layer changes from afirst pitch angle at a center portion of the bight to a second pitchangle at the termination end, wherein the at least one fiber layerincludes at least one fiber helically wound around the core.

Where the fiber layer comprises only one fiber, the fiber may be equallywound around the core from the center portion of the bight towards thetermination end in a clockwise (e.g., S-twist) or counterclockwise (e.g.Z-twist) direction. The fiber layer may comprise a plurality of fibers,wherein all fibers are wound around the core in the clockwise direction,or alternatively in the counterclockwise direction, from the centerportion towards the termination end of the core. In some embodimentswhere the fiber layer comprises multiple fibers, a first set of thefibers is wrapped around the core in a clockwise direction while asecond set of the fibers is wrapped around the core in acounterclockwise direction. By adding more fibers in a single layer offiber, the cable is able to achieve increased torque transmissioncapabilities. Similarly, wrapping additional layers of fiber around thecore improves the torque transmission capabilities of the cable. Inaddition, a cable having a fiber layer comprising fibers wrapped in bothclockwise and counterclockwise directions can transmit torque loaddifferently than a cable having a fiber layer comprising fibers wrappedin a common direction. As such, various torque transmissioncharacteristics may be achieved by adjusting the manner in which fibersare helically wound around the core.

The core of the cable may be a fiber, composite, or metallic tensilemember core, or may comprise any combination of fiber, composite, andmetallic materials.

In some embodiments, the first pitch angle of the fiber in the portionof the fiber layer disposed over the center portion of the bight isbetween thirty degrees (30°) and sixty degrees (60°). In otherembodiments, the first pitch angle is further restricted between fortydegrees (40°) and fifty degrees (50°). The second pitch angle of thefiber in the portion of the fiber layer disposed over the terminationend may be greater than the first pitch angle. In preferred embodiments,the second pitch angle is ninety degrees (90°). The angularconfiguration of the fiber from 40°-50° along the bight to 90° at thetermination end provides for advantageous transmission of torque loadthrough the bight and termination end. With the above configuration, thefiber layer provides high tensile strength, thereby enabling the cableto withstand tension applied axially on the cable. Further, the cableremains flexible when no load is applied on the cable at the terminationend.

The torque transmission cable may further comprise a groove in the coreproximate to the termination end. The groove is adapted to secure the atleast one fiber layer to the core such that the fiber in the portion ofthe fiber layer disposed over the termination end is secured at thesecond pitch angle. The groove also ensures that the fiber layer doesnot unravel from the core. In other embodiments, the cable may comprisea locking mechanism positioned proximate to the termination end, whereinthe locking mechanism secures the fiber layer so that the fiber disposedover the termination end is oriented in the second pitch angle.

To aid in the positioning of the fiber layer, and more specifically thefibers wrapped around the core at and/or near the termination end, thefibers within the groove may be impregnated with resin. Further, resinmay be applied to the entire length of the fiber layer. The addition ofresin to the fiber layer enhances the cable's capabilities to transfertorque loads. However, it is noted that resin is not required for thecable to possess efficient torque transmission characteristics.

The torque transmission cable may include an end fitting mounted to thecore at the termination end, wherein the end fitting is adapted tofurther secure the fiber layer to the core. The end fitting may alsoserve as means for connecting the cable to other maritime equipment,such as a furler drum and/or top swivel of a furling system.

Other objectives are achieved by providing a torque transmission cableincluding a core having at least one termination end and a bight, andtwo or more layers of fiber concentrically wound around the core. Forexample, the cable may have a first fiber layer and a second fiberlayer. At least one fiber in a portion of the first fiber layer disposedover a center portion of the bight has a first pitch angle relative to alongitudinal axis of the core while at least one fiber in a portion ofthe first fiber layer disposed over the at least one termination end hasa second pitch angle relative to the longitudinal axis of the core. Thefirst fiber layer comprises a first transition zone disposed between theat least one termination end and the center portion of the bight,wherein at least one fiber in the first transition zone has anorientation that transitions from the first pitch angle to the secondpitch angle. In addition, at least one fiber in a portion of the secondfiber layer disposed over the center portion of the bight has a thirdpitch angle relative to the longitudinal axis of the core while at leastone fiber in a portion of the second fiber layer disposed over the atleast one termination end has a forth pitch angle relative to thelongitudinal axis of the core. The second fiber layer comprises a secondtransition zone disposed between the at least one termination end andthe center portion of the bight, wherein at least on fiber in the secondtransition zone has an orientation that transitions from the third pitchangle to the fourth pitch angle. Additional fiber layers, for example athird and fourth fiber layers, may be included in the cable.

In some embodiments, the first and third pitch angles are less than thesecond and fourth pitch angles, respectively. For example, with regardto the first fiber layer, the second pitch angle may be go° while thefirst pitch angle may be between 40° and 50°. Similarly, with regard tothe second fiber layer, the fourth pitch angle may be go° while thethird pitch angle may be between 40° and 50°. The cable may beconfigured such that the second and fourth pitch angles match eachother. In similar respect, the first and third pitch angles may matcheach other. However, in some embodiments, the first pitch angle of thefirst fiber layer differs from the third pitch angle of the second fiberlayer and/or the second pitch angle of the first fiber layer differsfrom the fourth pitch angle of the second fiber layer.

The cable may be designed such that each fiber layer comprises at leastone fiber helically wound around the core. In some embodiments, eachfiber layer comprises multiple fibers helically wound around the core,either in the same direction or in opposite directions (i.e., clockwiseand counterclockwise). Moreover, the at least one fiber of each fiberlayer may be applied to the core at different lengths. Accordingly, thefiber in the first layer may be wrapped around the core with a firstlength while the fiber in the second layer may be wrapped around thecore with a second and different length. This arrangement of wrappingfibers of separate fiber layers at variable lengths provides for torquetransmission characteristics to vary along the length of the cable.

With multiple fiber layers, the cable includes multiple transitionszones. The transition zones, e.g., the first transition zone of thefirst fiber layer and the second transition zone of the second fiberlayer, may be aligned with each other such that they begin and/or end inthe same positions relative to the core. However, in some embodiments,the transition zones may not be fully aligned with each other. Thetransition zones of the fiber layers may be configured so that they havethe same lengths and therefore span the bight equally. Still, the cableneed not be designed with multiple fiber layers having transitions zonesof equal length. The transition zones of the fiber layers may havedifferent lengths. By varying the alignment of the transition zonesand/or the lengths of the transition zones, various torque transmissioncharacteristics may be achieved in the cable.

Other features and aspects of the invention will become apparent fromthe following detailed description, taken in conjunction with theaccompanying drawings, which illustrate by way of example, the featuresin accordance with embodiments of the invention. The summary is notintended to limit the scope of the invention, which is defined solely bythe claims attached thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C are schematic views of a torque transmission cable accordingto an exemplary embodiment of the present invention.

FIG. 2 is a schematic view of the torque transmission cable of FIG. 1showing the core partially wrapped by a layer of fiber.

FIG. 3 is a side view of a sailboat having the torque transmission cableof FIG. 1 integrated into a furling system.

FIGS. 4A-4D are schematic views of a torque transmission cable accordinganother exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description illustrates the invention by way ofexample, not by way of limitation of the principles of the invention.

As used herein, the term “cable” encompasses cordage, lines, wires, andropes that connect and manipulate the sails of a boat, such as riggingand furling the sails.

As previously noted, the term “bight” refers to the middle part of acable, as distinguished from the ends

Referring to the figures in detail and first to FIGS. 1A-1 c, 2 and 3,there is shown an exemplary embodiment of a cable 100 for rigging orfurling a sail 202 of a boat 200. The cable 100 is designed with acentral core 102 having at least one termination end 104 and a bight106. Often, the core 102 includes two termination ends 104 positioned onopposing sides of the bight 106. The core 102 may be made from naturalor synthetic fiber, composites, metallic alloys, or any combination ofthese materials. For example, the core may be made of polybenzoxazole(PBO). Aramids, such as Kevler® and Technora®, may also be used to makethe core 102. The core 102 is axially stiff, has high tensile strength,and is adapted to withstand the tension and torque load applied on thecable 100 when rigging or furling the sail 202 (see FIG. 3). However,when there is no load on the cable 100, the core 102 remains flexible.

In preferred embodiments, the core 102 is designed with a first diameteralong the bight 106 and a second diameter at the termination end 104.The second diameter is set to be greater than the first diameter. Thisconfiguration of the core 102 helps improve the cable's tensile strengthand ability to efficiently transfer torque loads applied at thetermination end. The core 102 is also constructed such that thetermination end having the second diameter tapers towards the bighthaving the first diameter. This feature ensures a smooth transfer oftension and torque load between the termination end 104 and the bight106.

The cable 100 includes at least one layer of fiber 112 (112 a, 112 b)firmly wound over and around the core 102. The fiber layer 112—and theindividual fibers therein—has high stiffness and is applied at hightension to reduce its play once it is wound around the core 102. Thefiber layer 112 also has high tensile and torsional strength.Accordingly, the performance of the fiber layer does not degrade afterbeing repeatedly subjected to tensile forces and/or torque load appliedon the cable during furling and unfurling of the sail 202. In someembodiments, the fiber layer 112 comprises a single fiber helicallywound around the core 102, either in a clockwise direction (e.g.,S-twist) or counterclockwise direction (e.g., Z-twist) from the bight106 towards the termination end 104. In other embodiments, the fiberlayer 112 comprises a plurality of fibers wrapped around the core 102 ina helical configuration. The multiple fibers may all be wrapped aroundthe core 102 in a clockwise or counterclockwise direction from the bighttowards the termination end. Alternatively, the fiber layer 112 may beconstructed with a first set of fibers wrapped around the core 102 in aclockwise direction while a second set of fibers is wrapped around thecore 102 in a counterclockwise direction.

The fiber(s) in the fiber layer may be a textile fiber, natural fiber(e.g., hemp, linen, cotton), or synthetic fiber (e.g., polypropylene,nylon, polyesters, polyethylene, aramids, acrylics). In the case wherethe fiber layer 112 includes multiple fibers, each of the fibers may becomposed of the same material. In other embodiments, the fiber layer mayinclude a collection of different types of fibers, in order to achievevarious tensile strength and torque transmission characteristics. Thefiber layer, for example, may have synthetic fibers and natural fibersadjacently wound around the core or an arrangement of polyester fibersand aramids wrapped around the core.

A feature of the cable 100 which provides for efficient torquetransmission characteristics is the angular configuration of the fiberin the fiber layer 112 wound around the core 102. In particular, atleast one fiber in the fiber layer 112, or more specifically in section112 b, disposed over a center portion 108 of the bight 106 has a firstpitch angle a relative to the longitudinal axis 110 of the core.Conversely, at least one fiber in the fiber layer 112, or morespecifically in section 112 a, disposed over the termination end 104 iswound around the core 102 such that the fibers have a second pitch angle13 relative to the longitudinal axis 110 of the core. Further, betweenthe termination end 104 and the center portion 108 of the bight, atransition zone 114 is introduced in the fiber layer 112. The fiber(s)disposed within the transition zone 114 is configured such that it hasan orientation which gradually changes from the first pitch angle a(defining the fiber located over the center portion of the bight) to thesecond pitch angle 13 (defining the fiber located over the terminationend). It is noted that, in some cases, the transition zone may providefor the pitch angle of the fiber(s) to shift by incremental jumps indegree, instead of a smooth and continuous transition.

The transition zone 114 extends over a section of the bight 106 of thecore 102 in some embodiments. For example, the transition zone 114 mayspan partially or entirely the portion of the core where the terminationend 104 tapers towards the bight 106. The transition zone 114 mayinstead span a length greater than the portion of the core where thetermination end tapers towards the bight (see FIGS. 1A-1C). In otherembodiments, the position of the transition zone 114 may be confined tothe termination end only. Still, in further embodiments of the cable100, the transition zone 114 may extend both the termination end 104 anda portion of the bight 106 adjacent to the termination end. Any of theseconfigurations of the transition zone provides for efficient torquetransmission characteristics in the cable.

In preferred embodiments, the first pitch angle a is less than thesecond pitch angle 13. The angular orientation of the fiber wrapping,therefore, increases from the center portion 108 towards the terminationend 104. The first pitch angle a of the fiber in the fiber layer 112disposed over the center portion 108 of the bight 106 is generallybetween 30° and 60°, inclusive. In further embodiments, the first pitchangle a is set between 40° and 50°, inclusive. The second pitch angle 13of the fiber in the fiber layer 112 disposed over the termination end104 is preferably go° When the second pitch angle 13 is go° the sectionof the fiber layer 112 disposed over the termination end (112 a), andmore specifically the at least one fiber therein, no longer wraps aroundthe core 102 in helical manner. Instead, the at least one fiber wrapsaround the core 102 in a concentric—or substantially concentric—manner.It is noted that once the fiber layer 112 transitions to go° at and/orproximate to the termination end 104, additional concentric wrapping ofthe at least one fiber at go° is provided. In particular, as shown inFIGS. 1A-1C, the fiber disposed within a groove 116 (discussed below infurther detail) is wrapped around the core 102 with a go° pitch angle.

With the above angular orientation and transitioning of the fiber layer112, and in particular the incorporation of go° fibers at thetermination end 104, the transmission of torque load through the cable100 can be maximized. Moreover, the angular orientation andtransitioning of the fiber layer provides for the cable to efficientlytransfer torque load without requiring the infusion of resin into thefibers. In contrast to the above configuration of pitch angles, thefiber layer 112 may be designed with the first pitch angle a beinggreater than the second pitch angle 13. Accordingly, the pitch angle ofthe fiber wrapping decreases from the center portion 108 of the bight106 towards the termination end 104.

Regardless of whether the first pitch angle is greater than or less thanthe second pitch angle, the core 102 with the at least one fiber layer112 provides for high axial stiffness when a load is applied to thecable. This characteristic is important since the application of hightensile load on the cable—and in general any luff rope/cable—isnecessary to achieve proper sail shape for stowing or dousing the sail.As the cable 100 is tensioned axially, the fibers within the fiber layer112 are also tensioned, thereby improving the cable's performance andresponse in rigging or furling operations. The cable 100 can withstandhigh tensile forces experienced during furling or unfurling the sail 202(see FIG. 3). In addition, when there is no load on the cable 100, itremains flexible. This feature of the cable provides for the cable to beeasily flaked or coiled in a relatively small diameter for stowage,without causing damage to the core 102 or the fiber layer 112 andwithout impairing the overall integrity of the cable.

The core 102 may include a groove or slot 116 at the termination end 104for securing the fiber in terminal section of the fiber layer (112 a) tothe core 102 at the second pitch angle 13. For example, the fiber layer112 a wrapped around and within the groove 116 is positively locked at90°. The groove 116 is further adapted to reduce the play of the fiberlayer disposed at the termination end 104 as well as the fiber layerdisposed along the bight 106. In some embodiments, the cable 100 uses alocking mechanism instead of a groove to positively lock the fiber layerincorporated into the termination end 104 at the second pitch angle 13.In other embodiments, the cable 100 includes both a groove 116 and alocking mechanism to secure the fiber layer to the core and reduce anyplay or movement of the fiber layer relative to the core.

The cable 100, with the features of the core 102, fiber layer 112,transition zone 114, and groove 116, is adapted for efficient torquetransmission, wherein, for example, one turn in the furler drum 204results in one turn at the top swivel 206, thus ensuring good furling ofthe sail 202 (see FIG. 3). The cable 100 is able to accommodate hightorque transfer loads in order to initiate furling as quickly aspossible. In other words, the cable is adapted such that the furler drum204 requires less number of turns before a corresponding top swivel 206begins to turn and wrap the top portion of the sail 202.

It is noted that the cable 100 is able to provide efficient torquetransmission without relying on resin and impregnating the fiber layer112 with resin. However, resin may be incorporated into the cable 100 inorder to further enhance the cable's tensile strength and torquetransmission capabilities as well as reinforce the positioning of thefiber layer. In some embodiments, resin is added in the groove 116, suchthat the fibers disposed therein are fused with resin. In otherembodiments, resin is applied in the groove and along the terminationend 104 of the core 102. Still further, the fiber layer 112, along theentire length of the cable (i.e., from center portion 108 of bight 106to the termination end 104 including groove 116) may be impregnated withresin.

As shown in FIGS. 1A-1C and 2, the cable 100 also includes an endfitting 118 mounted to the at least one termination end 104 of the core102. More specifically, the end fitting 118 is attached to the groove116 and is adapted to secure the fiber layer 112 to the core 102 andprevent the fibers from fraying. The end fitting 118 also serves as aconnection between the cable 100 and other maritime equipment, such as afurler drum 204 or a top swivel 206 of a furling system. Different typesof end fittings, including marine eye, lashing eye, spreader eye, fork,toggle, bi-conic socket, turnbuckle, threaded stud, headed stud, strop,halyard lock, etc., may be used in the cable 100.

Referring to FIGS. 4A-4D, another exemplary embodiment of the torquetransmission cable is disclosed herein. More specifically, a cable 300

includes a core 302 having two termination ends 304 and a bight 306between the ends 304. The core 302 comprises a first diameter along thebight 306 and a second diameter at the termination ends 304, wherein thesecond diameter is greater than the first diameter. A portion of thecore 302 tapers between the termination ends and the bight. Further, thecable 300 includes two or more layers of fiber (designated as elements311, 312) wrapped concentrically over and around the core 302. Byincluding multiple fiber layers 311, 312, wherein each fiber layerincludes a transition zone 314, the torque transmission characteristicsof the cable 300 are further enhanced as compared to a cable having onlyone fiber layer. Noted herein, for ease of illustration, FIG. 4A showsonly a portion of a second fiber layer 311 wrapped over the core 302.

Each of the fiber layers 311, 312 comprises one or more fibers. Eachfiber in first fiber layer 312 and second fiber layer 311 is helicallywound around the core 302. In some embodiments, all the fibers in agiven fiber layer are wound in a clockwise (e.g., S-twist) orcounterclockwise direction (e.g., Z-twist) from one termination end tothe other. Alternatively, a first subset of fibers in a given fiberlayer are wound in a clockwise direction while a second subset of fibersare wound in a counterclockwise direction. The fiber wrapping ofseparate fiber layers 311, 312 may also be designed to either match orvary. For example, the fibers in first fiber layer 312 and second fiberlayer 311 are both wound helically in a clockwise (or counterclockwise)direction. In contrast, the fibers in first fiber layer 312 may be woundin a clockwise direction while the fibers in second fiber layer 311 maybe wound in a counterclockwise direction.

As shown in FIG. 4A, each fiber layer comprises a portion disposed overa center portion 308 of the bight 306. In particular, the first fiberlayer 312 includes a portion 312 b having at least one fiber that isdisposed over the center portion of the bight and that has a first pitchangle of relative to the longitudinal axis 310 of the core 302. Thesecond fiber layer 311 includes a portion 311 b having at least onefiber that is disposed over the center portion of the bight and that hasa third angle 02 relative to the longitudinal axis 310. Each fiber layeralso comprises a portion having at least one fiber that is disposed overthe termination end 304 and that has a different pitch angleconfiguration. Specifically, the first fiber layer 312 has a portion 312a having at least one fiber that is disposed over the termination endand that is defined by a second pitch angle 131. The second fiber layer311 has a portion 311 a having at least one fiber that is disposed overthe termination end and that is defined by a fourth pitch angle 132. Itis noted that portion 311 a of second fiber layer 311 and fourth pitchangle 132 are not identified in FIGS. 4A-4D due to ease of illustratingmultiple fiber layers wrapped around the core.

Between the termination ends 304 and the center portion 308 of the bight306, each fiber layer 311, 312 has a transition zone 314. Accordingly,the fibers disposed within the transition zone of the first fiber layer312 are arranged such that they have an orientation which graduallytransitions from the first pitch angle 01 to the second pitch angle 131.On the other hand, the fibers disposed within the transition zone of thesecond fiber layer 311 are arranged such that they have an orientationwhich gradually transitions from the third pitch angle 02 to the fourthpitch angle 132.

In some embodiments, the first and third pitch angles 01, 02 are lessthan the second and fourth pitch angles 131. 132, respectively. As such,the angular orientation of the fiber wrappings in first fiber layer 312and second fiber layer 311 increases from the center portion 308 towardsthe termination end 304. The first pitch angle 01 and the third pitchangle 02 may be set to either coincide/match or differ in degrees.Similarly, the second pitch angle 131 and fourth pitch angle 132 may bethe same or different. However, it is preferable that the second andfourth pitch angles be set to the same degree, i.e. 90°. Regarding thefirst and third pitch angles, each angle is preferably between 40° and50°.

The position of the transition zones 314 of the fiber layers 311, 312relative to one another may vary. In some embodiments, the transitionzones 314 are aligned with each other such that they begin and/or end inthe same location on the core. In other embodiments, the transitionzones 314 may not be aligned, i.e., the beginning and end of each of thetransition zones 314 do not coincide. By adjusting the location of thetransition zones of each fiber layer on the core so that they arealigned (i.e., the start and/or end of the transition zones areparallel) or not aligned, the cable 300 can possess different torquetransmission and tensile strength characteristics.

The transitions zones 314 of the fiber layers 311, 312 may also vary intheir lengths. In other words, each transition zone may span the core302 differently. For example, the transition zone of one fiber layer mayextend the entire length of the bight 306 of the core 302 while thetransition zone of another fiber layer may extend only partially thelength of the bight 306. As another example, the transition zone of onefiber layer may extend over a section of the bight 306 while thetransition zone of another fiber layer extends both the termination end304 and a section of the bight 306. Conversely, the transition zones ofthe all the fiber layers may span the core 302 equally. For example, thetransition zone of each fiber layer may be set to span the core by onefoot (1 ft). As such, the transitioning of pitch angle of each fiberlayer occurs within a common length of the core. By adjusting thelengths of the transition zones of each fiber layer so that they are thesame or differ, the cable 300 can possess different torque transmissionand tensile strength characteristics.

The cable 300 can also be designed with variable fiber dimensionsbetween different fiber layers 311,312. For example, the fibers in thefirst fiber layer 312 may be wound around the core 302 with one fiberlength while the fibers in the second fiber layer 311 may be wrappedaround the core 302 with a different fiber length. By varying the fiberlengths between the fiber layers, the cable 300 can achieve torquetransmission characteristics which vary along the cable.

The cable 300 with multiple fiber layers 311, 312 may include a groove316 in the core 302 at the termination end 304, or a locking mechanismdisposed at the termination end 304, for securing the terminal sections312 a, 311 a of each fiber layer to the core 302 at corresponding secondand fourth pitch angles. The groove 316 (and locking mechanism) alsohelps to prevent play in each of the fiber layers 311, 312.

The cable 300 also includes an end fitting 318 mounted to thetermination end 304 adjacent to the groove 316. The end fitting 318 isadapted to secure the multiple fiber layers 311, 312 to the core 302 aswell as connect the cable 300 with other maritime equipment (e.g.,furler drum 204, top swivel 206).

In view of the above, the cable 100 and cable 300 are specificallyadapted to provide high tensile and torsional strength. These featuresare important since luff cables are subjected to high loads duringrigging and furling operations. Compared to conventional ropes andcables, such as braided or resin impregnated braided cables, the cable100 and cable 300 both provide superior torque transfer capabilities bygradually changing the angular orientation of fiber layer(s) from40°-50° to 90° and without relying on resin.

Although the invention has been described with reference to particulararrangement of parts, features, and the like, these are not intended toexhaust all possible arrangements or features, and indeed manymodifications and variations will be ascertainable to those of skill inthe art.

What is claimed is: 1.-12. (canceled)
 13. A cable adapted to transmittorque in rigging or furling a sail, said cable comprising: a corehaving at least one termination end and a bight; and a plurality oflayers of fiber concentrically wound around said core; wherein a firstfiber layer of said plurality of fiber layers has a portion having atleast one fiber that is disposed over a center portion of said bight andthat has a first pitch angle relative to a longitudinal axis of saidcore; wherein said first fiber layer has a portion having at least onefiber that is disposed over said at least one termination end and thathas a second pitch angle relative to said longitudinal axis of saidcore; wherein said first fiber layer comprises a first transition zonedisposed between said at least one termination end and said centerportion of said bight, wherein at least one fiber in said firsttransition zone has an orientation that transitions from the first pitchangle to the second pitch angle; wherein a second fiber layer of saidplurality of fiber layers has a portion having at least one fiber thatis disposed over said center portion of said bight and that has a thirdpitch angle relative to said longitudinal axis of said core; whereinsaid second fiber layer has a portion having at least one fiber that isdisposed over said at least one termination end and that has a fourthpitch angle relative to said longitudinal axis of said core; and whereinsaid second fiber layer comprises a second transition zone disposedbetween said at least one termination end and said center portion ofsaid bight, wherein at least one fiber in said second transition zonehas an orientation that transitions from the third pitch angle to theforth pitch angle.
 14. The cable of claim 13, wherein said first pitchangle and third pitch angle are between 40° and 50°, inclusive.
 15. Thecable of claim 14, wherein said first pitch angle matches said thirdpitch angle.
 16. The cable of claim 13, wherein said second pitch anglematches said fourth pitch angle.
 17. The cable of claim 16, wherein saidsecond pitch angle and said fourth pitch angle are 90°.
 18. The cable ofclaim 13, wherein said first and second fiber layers each comprises atleast one fiber helically wound around said core.
 19. The cable of claim18, wherein the at least one fiber of said first fiber layer differs inlength from the at least one fiber of said second fiber layer.
 20. Thecable of claim 13, wherein said first and second transition zones arealigned with each other.
 21. The cable of claim 13, wherein said firstand second transition zones span the core by different lengths.
 22. Thecable of claim 13, wherein said core comprises a groove at saidtermination end, said groove securing said first fiber layer and saidsecond fiber layer to said core such that said fiber in said portion ofsaid first fiber layer disposed over said termination end is secured atthe second pitch angle and such that said fiber in said portion of saidsecond fiber layer disposed over said termination end is secured at thefourth pitch angle; and wherein said first and second fiber layersdisposed within said groove are impregnated with resin.